Trip cause management device for an electronic trip device

ABSTRACT

A management device ( 1 ) of the causes of tripping in an electronic trip device enabling operation to take place in efficient and dependable manner by means of an architecture with three microcontrollers. The first microcontroller ( 3 ), second microcontroller ( 4 ) and third microcontroller ( 5 ), connected to one another, perform analysis and storage of characteristics typical to the electric power system ( 2 ) measured by the first microcontroller ( 3 ). Depending on the power supply situations and the analyzed events, one, two or three microcontrollers can be active to reduce the electric power requirements of the device ( 1 ). Storage of the data concerning the electric power system ( 2 ) is at least partially performed in redundant manner.

BACKGROUND OF THE INVENTION

The invention relates to a management device of the causes of trippingin a circuit breaker.

STATE OF THE ART

After tripping of an electronic circuit breaker, it is important to keepthe information concerning the cause of tripping. It is also importantto keep some information on the events which took place just beforetripping.

In traditional manner, the information related to the cause of trippingis generated by means of a microprocessor which stores this data onmemory devices. The microprocessor also performs storage of the dataconcerning the electric quantities before and at the time of tripping. Aheavy power demand is placed on the microprocessor during data storagewhich requires the use of a microprocessor of large size.

Several documents dealing with this issue exist. For example, thedocument EP0279692 describes a circuit interrupter with a faultindicator. The data concerning the state of the monitored power supplyjust before the fault is stored by a single microprocessor.

For the sake of simplicity, the circuit breaker is supplied directly bythe line to be monitored. In this configuration, when tripping occurs,the circuit breaker is no longer powered-on.

The document U.S. Pat. No. 5,089,928 describes a circuit breaker using amicro-computer for monitoring a circuit and for storing data concerningthe monitored circuit.

The document U.S. Pat. No. 5,311,392 discloses a circuit breakerequipped with two processors to monitor a power supply circuit. Theprocessors are powered in independent manner so that a second processoralso operates when the power supply of the first processor isinterrupted. The first processor has access to more information than thesecond processor.

The document U.S. Pat. No. 5,224,011 discloses a system where a batteryis used to perform data storage in an electric circuit in case ofunavailability of the main power supply.

OBJECT OF THE INVENTION

It is observed that a requirement exists to provide a circuit breakerproviding information on the causes of tripping in a more efficient andmore dependable manner.

This object is achieved by a circuit breaker comprising:

-   -   a series of inputs designed to be connected to a first        microcontroller configured to measure characteristics of an        electric current of a power supply line to detect an electric        fault of the power supply line,    -   a second microcontroller supplied by said power supply line and        presenting a first electricity consumption value, the second        micro-controller being configured to analyse data coming from        the first micro-controller in order to detect an electric fault        of the power supply line,    -   a third microcontroller supplied by said power supply line and        connected so as to receive data from the first and second        microcontrollers, the third microcontroller being configured to        indicate the cause of tripping of the circuit breaker, the third        microcontroller presenting a second electricity consumption        value that is lower than the first electricity consumption        value,    -   a back-up power supply source configured to supply the third        micro-controller in case of unavailability of the power supply        line.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and features will become more clearly apparent from thefollowing description of particular embodiments of the invention givenfor non-restrictive example purposes only and represented in theappended drawings, in which:

FIG. 1A illustrates a first embodiment of a circuit breaker in schematicmanner,

FIG. 1B illustrates a second embodiment of a circuit breaker inschematic manner,

FIG. 2 illustrates a flowchart with the main actions performed by thecircuit breaker,

FIGS. 3A and 3B represent two embodiments of a circuit breaker inschematic manner,

FIG. 4 represents a flowchart of the steps for management of the stateof the battery,

FIG. 5 represents the times and the cycles sequencing the variations ofthe current emitted by the battery in the scope of a battery dischargemanagement method,

FIG. 6 represents examples of the variation versus time of the electricvoltage measured at the terminals of the battery.

DETAILED DESCRIPTION

FIGS. 1A and 1B show a monitoring device 1 of electric power supplylines of an electric power system 2. In advantageous manner, monitoringdevice 1 forms part of a circuit breaker connected to one or moreelectric power supply lines of electric power system 2. The monitoringdevice analyses these lines in order to determine whether they areoperating normally or malfunctioning. The circuit breaker is configuredto analyse the electric characteristics of the power supply line to bemonitored by means of micro-controllers and to trigger disconnection ofthis power supply line if an electric fault is detected. Device 1 cancomprise a first microcontroller 3, a second microcontroller 4 and athird microcontroller 5 the specificities of which will be definedfurther on. As a variant, first microcontroller 5 is located outsidemonitoring device 1 but it is connected to a series of inputs of device1 so as to provide data on electric quantities representative ofelectric power system 2 to the latter.

First microcontroller 3 is connected to the power supply line ofelectric power system 2. First microcontroller 3 is equipped withmeasuring means 6 to measure quantities characteristic of electric powersystem 2 (step F1), such as for example the voltage V, current I andfrequency f. First microcontroller 3 can be integrated in the circuitbreaker or be located outside the circuit breaker. First microcontroller3 is also configured to monitor electric power system 2 and to detect apossible fault.

In an advantageous embodiment, first microcontroller 3 is electricallysupplied by a primary power supply 7 which is provided by the electricline to be monitored. This primary power supply 7 is the main electricpower source of first microcontroller 3. As power supply of the circuitbreaker and more particularly of monitoring device 1 is performed byelectric power system 2 or is branched off from this power system 2, incase of tripping of the circuit breaker the primary power supply line isinterrupted and first microcontroller 3 is no longer powered-on.Furthermore, the power delivered by primary power supply 7 can varyaccording to the electric load connected to the electric power system.

A back-up electric power supply source is provided by a first electriccapacitor 8 to supply first microcontroller 3 during a limited time,when its primary power supply 7 is interrupted. In this way, when thetripping order is sent to the circuit breaker or when firstmicrocontroller 3 detects loss of the primary power supply, there isenough energy remaining in capacitor 8 to perform transfer of therelevant data to the other components of the circuit breaker. Thisback-up power supply 8 allows recording of the important electric datawhen an electric fault is detected on the power supply line.

First microcontroller 3 can detect a fault of the electric power systemand trigger disconnection of the electric power system. Data concerningelectric power system 2 and more particularly the monitored line iscommunicated to different components of the circuit breaker via a firstcommunication line 9 from first microcontroller 3.

In a particular embodiment illustrated in FIGS. 1A and 1B, a secondmicro-controller 4 is connected to first microcontroller 3 by means offirst communication line 9. In this way, second microcontroller 4receives data concerning electric power system 2 via firstmicrocontroller 3. Second micro-controller 4 can also receive dataconcerning electric power system 2 from other devices of the monitoringdevice. These other devices provide measurements of the electricquantities of the electric power system.

The main function of second microcontroller 4 is to analyse and storethe data concerning electric power system 2. Second microcontroller 4performs a more in-depth analysis of the measured electric quantitieswhich enables a more detailed study of the electric power system to bemade (step F2). In this configuration, second microcontroller 4 canrequest disconnection of the power supply system for problems notdetected by first microcontroller 3, for example a voltage drop below athreshold and/or an abnormal frequency change. Second microcontroller 4is also configured to perform more precise analyses of the electriccharacteristics of the line to be monitored, for example voltage,frequency and/or harmonics measurements, and to transmit this data tothe user and/or to other computation modules.

For an in-depth analysis of the data concerning electric power system 2,second microcontroller 4 needs a large quantity of electric power. Thispower can also be used to transmit the collected data to othercomputation modules or to the user. For its power supply, secondmicrocontroller 4 is connected to primary power supply 7. Inadvantageous manner, second microcontroller 4 is supplied by means of aDC/DC power supply which is itself supplied by primary power supply 7.As previously, in case of malfunctioning of the electric power system orif primary power supply 7 cannot supply the necessary power, secondmicrocontroller 4 is no longer able to function.

A back-up second electric power source is provided by a second capacitor8′ to supply second microcontroller 4 during a limited time when itsprimary power supply 7 is interrupted. In this way, when the trippingorder of the circuit breaker is sent or when second microcontroller 4detects loss of the primary power supply, there is enough energyremaining in capacitor 8′ to allow transfer the relevant data to theother components of the circuit breaker.

Second microcontroller 4 is connected to a memory 10. Memory 10 isadvantageously supplied by means of primary power supply 7. In case ofmalfunctioning of primary power supply 7, it is advantageous to connectmemory 10 to a back-up power supply source which is formed by acapacitor 11 to provide the electric power during a limited time. Inthis way, the data calculated by second microcontroller 4 can berecorded in memory 10.

Memory 10 is advantageously of electrically erasable and programmablenon-volatile memory type or of random access memory with permanentmagnetic recording type or other enabling the data to be written easilyand to be kept even without any electric power supply. A user can thenread the recorded data.

Data transfer between second microcontroller 4 and memory 10 isperformed by means of a second communication line 12. Typically, thestored data originates from analysis of the information concerningelectric power system 2. For example, the data concerns a variation withtime and/or one-time values of current I, of voltage V or of frequency fof an alternating current present in electric power system 2.

In advantageous manner, second microcontroller 4 is configured toperform computations of harmonics which requires execution ofcomputations of Fourier transforms which are extremely power-consuming.

A third microcontroller 5 is present and connected to secondmicrocontroller 4 with a protocol enabling data transfer in bothdirections. For its power supply, third microcontroller 5 is connectedto primary power supply 7. In advantageous manner, third microcontroller5 is connected to the same power supply as second microcontroller 4, forexample by means of the DC/DC converter.

Advantageously, third microcontroller 5 is associated with a back-upelectric power supply 13, which is a source independent from electricpower system 2. This power source can for example be a battery 13.Battery 13 is an electrochemical device which converts chemical energyinto electric energy by means of a redox chemical reaction. Battery 13can be non-rechargeable and be referred to as a disposable battery orelectric battery. A battery is advantageous compared with a capacitor asit is more easily replaceable in case of malfunctioning.

In case of unavailability of primary power supply 7, thirdmicrocontroller 5 is supplied by battery 13. Battery 13 is configuredwith third microcontroller 5 so that third microcontroller 5 ispowered-on for a longer time than the first and second microcontrollersin case of unavailability of the primary power supply. Preferably,battery 13 is configured with third microcontroller 5 to supply apermanent power supply of third microcontroller 5. What is meant bypermanent power supply is providing the power supply of thirdmicro-controller 5 over a markedly longer period than the time requiredfor a maintenance operation so that the primary power supply isre-established before the battery power has run out. To obtain such aresult, third micro-controller 5 presents reduced functionalitiesconsuming little power. Third microcontroller 5 presents functionalitiesof presentation of the data computed in the first and/or secondmicrocontrollers. Third microcontroller 5 presents an electricityconsumption that is lower than the electricity consumption of secondmicrocontroller 4. For example, third microcontroller 5 is not providedwith Fourier transform computation means. This results in the secondmicrocontroller presenting a higher electricity consumption than theelectricity consumption of the third microcontroller.

Such a configuration enables second microcontroller 4 to be dedicated tohigh power-consuming operations in order to perform fine analysis of theelectric power system from the data provided by first microcontroller 3and/or by other devices supplying measurements of electric quantities ofelectric power system 2, and also advantageously enables transmission ofall or part of this data to the user or to other components of thecircuit breaker.

Third microcontroller 5 is dedicated to communication operations of thedata on the causes of tripping in particular with the user, whichrequires less power. Advantageously, the third microcontroller performsdisplay of the causes of tripping. After tripping of the circuitbreaker, it is no longer necessary to analyse the electric power systemwhich is interrupted, but it is however important to know the reasonsthat caused the tripping and therefore shutdown of the power supply bythe power system. It is therefore not necessary to maintain operation ofsecond microcontroller 4 and on the contrary it is important to supplythird microcontroller 5 to collect the relevant data and make itavailable.

Dissociation of the functionalities between two microcontrollers havingdifferent electricity consumptions makes it possible to perform all thedesired functions when the primary power supply is present and to ensurethat the relative data is provided after disconnection over a period oftime which may be long. This particularity also enables a compact androbust device to be provided as it is no longer necessary to provide aback-up power supply which supplies all the components of the circuitbreaker.

Capacitors 8 and 8′ perform power supply of first and secondmicro-controllers 3 and 4 during a short time period so as to be able torecord the electric characteristics of the power system before and justafter disconnection. This data is recorded in memory 10. As memory 10 isalso supplied by a back-up power supply source 11 of capacitor type,third micro-controller 5 is able to retrieve this data.

As the microcontrollers are supplied by primary power supply 7, thelatter may not be able to deliver a power necessary for correctoperation of second microcontroller 4. This scenario can occur whenthere is only a small load on the electric line or if an earth faultoccurs. If a fault is detected by first micro-controller 3, the latterinforms third microcontroller 5 and the data is stored without secondmicrocontroller 4 intervening in the case where a direct communicationline exists between first microcontroller 3 and third micro-controller5.

Advantageously, third microcontroller 5 has first analysis means 14configured to analyse characteristics of the electric power system andadvantageously to analyse strong currents I and high voltages V ofelectric power system 2. This data can easily be calculated and thecomputations only consume little energy. Third microcontroller 5 may beused to detect a malfunction in the electric power system (step F3).

Advantageously, second microcontroller 4 for its part has secondanalysis means 15 configured to only analyse weak or strong currents Iand high voltages V that are present on electric power system 2.Preferably, the analyses performed by second microcontroller 4 originatefrom data provided by first microcontroller 3 or by other devices whichprovide measurements on the electric quantities of electric power system2. In this case, there is no risk of overvoltage tripping and thirdmicrocontroller 5 can also be configured to perform the appropriateanalyses of the power system. This configuration makes it possible tohave a circuit breaker which is functional over a wider current range I.

In order to facilitate data retrieval in third microcontroller 5,different data items are advantageously sent from second microcontroller4. Second micro-controller 4 sends information on its own presence bymeans of a synchronization signal. Thus, if second microcontroller 4 isno longer powered-on, third microcontroller 5 detects this state by theabsence of a synchronization signal. Second microcontroller 4 also sendsa signal indicating that the electric power system disconnection orderhas been initialised in order to facilitate retrieval of the electricdata (step F5) by initiating data retrieval as early as possible.

In a particular embodiment illustrated in FIG. 1A, at least twocommunications lines are used. A first communication line 9 is usedbetween the three microcontrollers 3, 4 and 5 advantageously fortransfer of the data concerning electric power system 2. Two branchesare branch-connected so that microprocessors 4 and 5 receive the samedata. A synchronization line 16 connecting second microcontroller 4 andthird microcontroller 5 also enables data exchange. Synchronization line16 enables the microcontroller in charge of read of the data to bedefined. In advantageous manner, so long as second microcontroller 4 ispowered-on, it has priority or exclusivity to read and analyse the dataprovided by first microcontroller 3. Third micro-controller 5 can remainon hold or even on standby as there is no tripping of the circuitbreaker. An indication line 17 indicates disconnection of the powersystem and the cause detected by second microcontroller 4 (steps F5 andF6) by a specific signal.

In another particular configuration illustrated in FIG. 1B, at least twodifferent communication lines are used. A first communication line 9 isused for transfer of the data concerning electric power system 2 betweenfirst microcontroller 3 and second microcontroller 4. A secondcommunication line 9′ is used for transfer of the data concerningelectric power system 2 between second microcontroller 4 and thirdmicrocontroller 5. A synchronization line 16 connecting secondmicrocontroller 4 and third micro-controller 5 also enables dataexchange. Synchronization line 16 enables the microcontroller in chargeof read of the data to be defined as for the previous embodiment. Inadvantageous manner, so long as second microcontroller 4 is powered-on,it reads and analyses the data provided by first micro-controller 3.Third microcontroller 5 remains on hold or even on standby as there isno tripping of the circuit breaker. Indication line 17 indicatesdisconnection of the power system and the cause detected by secondmicro-controller 4 (steps F5 and F6) by a specific signal.

In the two particular cases of embodiments illustrated in FIGS. 1A and1B, indication line 17 enables second microcontroller 4 to communicateto third microcontroller 5 for example data resulting from its analysisof electric power system 2. In this way, third microcontroller 5 doesnot have to continuously analyse the data concerning electric powersystem 2 received by communication line 9 or 9′. Advantageously, thirdmicrocontroller 5 has a standby mode in which it does not consume anyelectric power. In this way, monitoring device 1 enables operation in amore efficient manner in terms of electric power. Third microcontroller5 leaves standby mode when it receives for example a start-up signalfrom first microcontroller 3 or from second microcontroller 4. Forexample on receipt of a signal indicating tripping of the circuitbreaker, third microcontroller 5 will retrieve data coming from thememories (for example memory 10) which is supplied by the first and/orsecond microcontrollers (step F7 and F8).

In also advantageous manner, third microcontroller 5 is configured toleave standby state failing receipt of a synchronization signal. Thus,if the power delivered by the main source is insufficient, data can bestored in memories 10 and 19 even if second microcontroller 4 isinactive.

In an advantageous embodiment illustrated in FIG. 1A, firstmicrocontroller 3 is connected to second and third microcontrollers 4and 5 by means of two connections branch-connected on line 9. In thisway, the two microcontrollers 4 and 5 receive the same data coming fromfirst microcontroller 3.

In even more advantageous manner and as illustrated in FIG. 1A, datatransfer is performed by means of a buffer memory 18. A first buffermemory 18 a makes the connection between first microcontroller 3 andsecond micro-controller 4 and a second buffer memory 18 b makes theconnection between first microcontroller 3 and third microcontroller 5.There is therefore a first communication line provided with a buffermemory 18 a and which connects first microcontroller 3 with secondmicrocontroller 4. There is also a second communication line providedwith a buffer memory 18 b and which connects first microcontroller 3with third microcontroller 5.

In an advantageous embodiment illustrated in FIG. 1B, firstmicrocontroller 3 is connected to second microcontroller 4 then secondmicrocontroller 4 is connected to third microcontroller 5 by means oftwo different connections respectively noted 9 and 9′. In this way,microcontroller 5 receives the data from first microcontroller 3 viasecond microcontroller 4.

In even more advantageous manner and as illustrated in FIG. 1B, datatransfer is performed by means of a buffer memory 18. A first buffermemory 18 a makes the connection between first microcontroller 3 andsecond micro-controller 4 and a second buffer memory 18 b makes theconnection between second microcontroller 4 and third microcontroller 5.There is therefore a first communication line provided with a buffermemory 18 a and it connects first microcontroller 3 with thirdmicrocontroller 5. There is also a second communication line providedwith a buffer memory 18 b and which connects second microcontroller 4with third microcontroller 5.

In advantageous manner in the embodiments illustrated in FIGS. 1A and1B, second microcontroller 4 emits a synchronization signal to thirdmicro-controller 5 to define the read priority on buffer memories 18,18′.

In also advantageous manner, first microcontroller 3 is connected to theother two microcontrollers 4 and 5 by means of one of communicationlines 9 and 9′ serving the purpose of indicating transmission of a faultin the electric power system, which results in a disconnection request(steps F4 and F5). The use of one of these communication lines enablesrecording of the data on the causes of the disconnection to be secured.

In a particular embodiment illustrated in FIGS. 1A and 1B, thirdmicro-controller 5 is connected to a second memory 19 in order to beable to store the data from microcontroller 5. In this way, a part ofthe data is recorded twice. There is a redundancy between memories 10and 19 which enables data to be retrieved more easily in case of aproblem affecting the integrity of the circuit breaker.

In advantageous manner, if third microcontroller 5 detects that memory10 is no longer powered-on, it records the data in another memory, forexample the internal memory of microcontroller 5, but the latter ishowever a volatile memory. It is also possible to store this data inmemory 19.

In a preferred embodiment, the first second and third microcontrollersdo not exchange data directly. Data exchanges are performed by means ofmemories which are common to two microcontrollers, for example memory 10and/or memory 19, or by means of parallel communication lines eachprovided with a memory, for example buffer memories 18 of line 9 and/orline 9′.

The configuration illustrated in FIG. 1A advantageously makes itpossible not to use third microcontroller 5 which can then be in astandby mode for a large part of the operating time of circuit breaker1.

Transmission means 20 are preferably connected to second memory 19and/or to memory 10 to make transmission of the recorded data easier.The user can receive and read the data concerning electric power system2 without using third microcontroller 5 which enables the consumed powerto be limited. For example, transmission means 20 transmit dataconcerning electric power system 2 by a near field communication, or byanother communication based on electromagnetic waves.

It is advantageous to couple third microcontroller 5 with one or moreindication devices (step F9) in order to facilitate reading of thecauses responsible for tripping of the circuit breaker. Thirdmicrocontroller 5 has an indication output 21 which is configured toindicate information to the user derived from the data concerningelectric power system 2. This indication can for example be performed bymeans of light-emitting diodes which are connected to indication output21. Thus, in case of tripping, the user knows very rapidly whethertripping of the circuit breaker is linked to a problem of overload,voltage surge, earth leakage, an overvoltage or another incident, whichquickly puts the user on the right track in his search to find thecauses of the incident.

In advantageous manner, the circuit breaker comprises a clock 22 whichenables the different events occurring to be date-stamped. For example,the recording is associated with a date in order to determine thechronological evolution of the different electric parameters withrespect to one another.

In one embodiment, first microcontroller 3 is a microcontroller of the“Application-Specific Integrated Circuit” type which measures thecurrent I and voltage V of electric power system 2 continuously. When itdetects a fault in electric power system 2, it indicates this to secondmicrocontroller 4 and to third microcontroller 5 and triggersinterruption of the current present in electric power system 2.

Operation of monitoring device 1 can be guaranteed in two operatingsituations. In the first operating situation, electric power system 2makes a large amount of electric power flow, for example a current ofabout or greater than 25% of the rated current of the circuit breaker,which results for circuit breaker 1 in monitoring of high values forcurrent I and/or for voltage V. In this situation, the primary powersupply is sufficient to supply all the components of management device1. In this case, second microcontroller 4 is able to analyse the dataconcerning electric power system 2 and it continuously stores datarelated to power system 2 in memory 10 and it can consult the datastored in memory 10. Third microcontroller 5 can be in a standby mode,as second microcontroller 4 performs analysis of the data concerningelectric power system 2.

In this operating situation, when first microcontroller 3 detects afault in power system 2, it triggers disconnection of power system 2.The main power supply 7 is also interrupted as it is derived from theelectric power system 2. By means of first capacitor 8, firstmicrocontroller 3 can inform third microcontroller 5 which is suppliedby back-up power supply 13.

By means of clock 22, third microcontroller 5 can date-stamp thedisconnection initiated by first microcontroller 3 and store the date insecond memory 19. By means of second communication line 12, thirdmicrocontroller 5 can read the data related to analysis of electricpower system 2 which was written by second microcontroller 4 in firstmemory 10 before the fault occurred in power system 2 and during theoccurrence of the fault in the power system. Third microcontroller 5 cantransmit all the data to transmission means 20 which can send it to theuser. Third microcontroller 5 can also send a signal corresponding tothe cause of tripping via indication output 21 to inform the user, forexample by means of several light-emitting diodes. All the data relatedto power system 2 is thus transmitted to the user.

In a particular operating mode that is able to be combined with theother operating modes, clock 22 is shared by third microcontroller 5,second micro-controller 4 and first microcontroller 3. As a variant,each microcontroller can be associated with a specific clock or a clockcan be common to two micro-controllers.

In the second operating situation, electric power system 2 makes a weakelectric current flow, for example less than 20% of the rated current ofthe circuit breaker. Consequently, primary power supply 7 is notsufficient for operation of second microcontroller 4. In this case,first microcontroller 3 sends the data concerning the electric powersystem to third microcontroller 5. If first microcontroller 3 detects afault of electric power system 2, only third microcontroller 5 cananalyse the cause of the fault and store the data concerning powersystem 2.

As indicated in the foregoing, it is advantageous to have a thirdmicro-controller 5 provided with a standby state in which theconsumption is extremely reduced or zero. As third microcontroller 5 isnot used for analysis of the operating conditions of the power supplyline, it is on standby most of the time.

In advantageous manner, third microcontroller 5 is configured so as toleave a standby state on receipt of a signal from the first and/orsecond micro-controller indicating an activity of electric power system2 or detection of an electric fault. Thus, in normal operation of thecircuit breaker for monitoring of the power system, thirdmicrocontroller 5 is in standby state, and when an activity or anelectric fault is detected, third microcontroller 5 is activated inorder to retrieve the relevant information before final disconnection ofthe other two microcontrollers 3 and 4.

In the embodiments illustrated in FIGS. 1A and 1B, the microcontrollersand memories are supplied between the same reference voltage 23 which isthe ground here and a voltage derived from the primary power supply. Asa variant, it is possible to use different reference voltages for eachmicro-controller and/or for each memory.

In an advantageous embodiment, it is possible to activate thirdmicro-controller 5 in periodic manner or on an order from the user toperform one or more other functions.

In a particularly advantageous embodiment, monitoring device 1 comprisesa management system of discharge of battery 13. It has in fact beendiscovered that in certain cases, on actuation of the circuit breaker,the battery is no longer powerful enough to supply third microcontroller5.

The operation described in the foregoing can be summed up in FIG. 2.First and second microcontrollers 3 and 4 and possibly thirdmicrocontroller 5 perform analysis of the electric quantities ofelectric power system 2 (steps F1, F2 and F3). The electric power systemis noted “primary line”.

If at least one of the microcontrollers detects an anomaly on electricpower system 2, it sends a signal which is, for a circuit breaker, theorder to disconnect the power supply. The power supply is interrupted ina step F4 and the same is therefore the case for the primary powersupply of the circuit breaker. At the same time as or consecutively tothe disconnection order, information is transmitted by firstmicrocontroller 3 and/or by second micro-controller 4 to thirdmicrocontroller 5 in order to inform of disconnection of the powersupply (step F6). As indicated previously, third microcontroller 5retrieves the relevant data concerning the electric power system (stepF7) from the first and second microcontrollers and/or from buffermemories 18 of the communication lines and/or from memories 10 and 19.The collected and possibly analysed data is transferred to memory 10 andpossibly to memory 19 (step F8). In addition to recording, the deviceindicates the type of malfunction that caused disconnection of theelectric power system (step F9).

As indicated in the foregoing, in a particularly advantageousembodiment, the monitoring device comprises a management device ofdischarge of battery 13. It has in fact been observed that in certainsituations, when tripping of the circuit breaker takes place, battery 13was not able to supply power to third microcontroller 5. In a standardconfiguration, the circuit breaker is not designed to trip regularly,and it is rare to use the back-up power supply. It is thereforeimportant in this exceptional situation for the monitoring device to beable to assist the user in troubleshooting to find the cause of theelectric fault.

FIG. 3A illustrates a monitoring device 1, for example a circuitbreaker, configured to monitor one or more electric power supply lines.Monitoring device 1 is designed to be connected to the electric powersupply lines and is configured to measure the electric characteristicsof the lines, for example the voltage present on the line and/or thecurrent flowing in the electric line. In the case of a circuit breaker,disconnection of the monitored power supply line can occur in case ofdetection of a malfunction.

Monitoring device 1 comprises a series of power supply terminalsdesigned to be connected to a primary power supply source 2. The primarypower supply source is the main power supply source, i.e. it mainly oras a priority supplies power to the different components of monitoringdevice 1.

In order to palliate a deficiency of primary power supply source 2,monitoring device 1 comprises a back-up power supply source 13 which isformed by a battery. Battery 13 is provided with two contacts 13 a whichconnect battery 13 to the components of monitoring device 1. Inadvantageous manner, all the electronic circuitry or only a part of theelectronic circuitry of monitoring device 1 is supplied by battery 13 inorder to keep a large autonomy in case of unavailability of main powersupply 2. In advantageous manner, battery 13 supplies at least a storagecircuit 24 which records indicators linked to the measured electricquantities. In the case of a circuit breaker, storage circuit 24preferably records indicators linked to the causes of tripping of thecircuit breaker.

Back-up power supply source 13 is placed in monitoring device 1 so as toprevent fitting of a new series of power supply lines dissociated fromthe first series of power supply lines. In this way, it is possible tohave a monitoring device 1 which is compact and which ensures almostpermanent operation.

As monitoring device 1 is placed in aggressive environments, it isadvantageous to have a back-up power supply source 13 which is also ableto withstand such conditions.

In an advantageous embodiment, monitoring device 1 is configured so thatprimary power supply source 2 is the power supply line to be monitoredor is linked to the power supply line to be monitored. The power supplyline to be monitored is designed to supply one or more other electricloads. If monitoring device 1 detects a malfunction on the power supplyline, it will cause disconnection of the line which will result inoutage of primary power supply source 2.

Thus, in this configuration, when the power supply line to be monitoredis shut down, main power supply 2 is lacking and it is necessary toswitch over to back-up power supply 13.

As represented in FIG. 3A, monitoring device 1 comprises a controlcircuit represented here by at least microcontrollers 4 and 5. Thiscontrol circuit is configured to analyse the power supply line to bemonitored. Storage circuit 24 is coupled to the control circuit. In theembodiment illustrated in FIGS. 3A and 3B, storage circuit 24 forms partof the control circuit and advantageously forms part of thirdmicrocontroller 5.

Battery 13 is configured to supply the control circuit or a part of thecontrol circuit (in particular storage circuit 24) in case of failure ofmain power supply 2. The battery advantageously supplies thirdmicrocontroller 5 which enables good performances of monitoring device 1to be ensured.

Monitoring device 1 further comprises a management circuit 25 configuredto analyse the state of battery 13 and to detect a possiblemalfunctioning of battery 13.

The use of a management circuit 25 which checks the state of battery 13makes it possible to know, in the course of time, whether back-up powersupply source 13 is able to supply storage circuit 24 and advantageouslythird microcontroller 5, and therefore to ensure satisfactory operationof monitoring device 1 when the main power supply is unavailable.

Measuring means 26 are configured to measure the voltage V_(bat) at theterminals of battery 13. Measuring means 26 are connected to an input ofa comparator 27 to provide it with information on the state of battery13 by means of the voltage V_(bat).

Measuring means 26 can be configured to perform measurement of thevoltage at the terminals of battery 13 in periodic manner, a periodsymbolised by Δt_(m), in FIG. 5, for example by means of clock 22. It isalso possible to perform measurement of battery 13 on receipt of ameasurement signal. The term measured voltage V_(bat) can represent thevoltage at the terminals of battery 13 or a quantity representative ofthis voltage. In a particular embodiment, the voltage at the terminalsof the battery V_(bat) is measured every 24 h, i.e. Δt_(m)=24 h.

The comparator 27 is configured to compare the measured voltage V_(bat)with a first threshold V_(OFF) and with a second threshold V_(min). Thesecond threshold V_(min) is higher than the first threshold V_(OFF).

The value of the second threshold V_(min) corresponds to a functionalbattery 13. Thus, if the measured voltage V_(bat) is higher than thesecond threshold value V_(min), comparator 27 emits first datarepresentative of this comparison and battery 13 is considered to befunctional by the management circuit.

The interval comprised between the first threshold value V_(OFF) and thesecond threshold value V_(min) corresponds to a battery 13 that maypresent a problem that is able to be corrected. Thus, if the measuredvoltage V_(bat) is comprised within this interval, comparator 27 sendsassociated second data to the management circuit.

The value of the first threshold V_(OFF) corresponds to a defectivebattery 13 that is unable to be repaired. Thus, if the measured voltageV_(bat) is lower than the first threshold value V_(OFF), comparator 27emits third data representative of this comparison and battery 13 isconsidered to be defective. Battery 13 has for example to be replaced.

The data emitted by comparator 27 is sent to management circuit 25. Ifmanagement circuit 25 receives the first data, it can store this data ina memory.

If management circuit 25 receives the third data, it can inform the userthat battery 13 is defective and that replacement of the latter is to bescheduled in order to maintain operation of monitoring device 1 with allits performances. Indication of a defective battery 13 can be performedby means of a light indicator, for example by means of a light-emittingdiode. It is also possible to use an electromagnetic wave or anelectronic signal to inform the user of failure of battery 13. Forexample, management circuit 25 indicates the end of life of battery 13by means of an output 21 or another dedicated output.

If management circuit 25 receives the second data, it engages a testprotocol in order to determine whether battery 13 is functional ordefective.

Management circuit 25 is coupled to an electric load 28 configured todischarge battery 13. Under these conditions, an electric current flowsfrom battery 13 to electric load 28 (through terminals 13 a of battery13).

Partial discharge of battery 13 is thus triggered when the measuredvoltage V_(bat) at terminals 3 a of battery 13 is higher than the firstthreshold V_(OFF) and lower than the second threshold V_(min).

Discharge of battery 13 is triggered by management circuit 25 whichdefines the discharge conditions, for example the current intensity, thecurrent duration, the quantity of electric charges transferred bybattery 13, the form of the current in time (intensity versus time)and/or the number of repetitions of a discharge current defining apattern.

A discharge current I_(d) is emitted from battery 13, and the dischargecurrent I_(d) is configured to at least partially eliminate apassivation layer present on a terminal or one of the internalelectrodes of battery 13.

For example, the discharge current I_(d) is in the form of severalpulses of square shape.

In one embodiment, management circuit 25 is connected to the controlelectrode of a switch 29. Switch 29 electrically connects the twoterminals 13 a of battery 13 or it connects one of the terminals 13 a ofbattery 13 to a reference potential 23 which is able to drain theelectric loads. This embodiment is advantageous as it is compact andenables flow of the current from battery 13 to be easily controlled.

In an even more particular embodiment, switch 29 is a transistor.Transistor 29 enables a discharge current I_(d) to transit from theanode of battery 13 to the reference potential 23 through electric load28. The reference potential 23 is for example the ground. The use of atransistor 29 associated with electric load 28 enables an extremelycompact device to be achieved while at the same time allowing a goodcontrol of the quantity of current to be made to transit. Transistor 29enables the current flow duration to be fixed and electric load 28enables the current intensity to be fixed.

Monitoring device 1 advantageously comprises a counter 30 which isconfigured to measure a quantity representative of the flow ofelectrons.

For example, monitoring device 1 advantageously comprises a counter 30which is configured to measure the quantity of current flowing throughterminals 13 a of battery 13 or to measure the number of iterations ofapplication of current flowing through terminals 13 a of battery 13.Counter 30 can be a counter which receives data from management circuit25 indicating tripping of a discharge current I_(d). Counter 30 thenrecords the number of iterations of application of discharge currentI_(d). Counter 30 can also be a counter measuring activation of thecontrol electrode of switch 29. Counter 30 can further be a measurementdevice of current I_(d) flowing through battery 13. The recorded data isthen a quantity of electrons that have transited via terminals 13 a ofbattery 13.

In a particular embodiment, management circuit 25 is connected tocounter 30. Management circuit 25 is configured to indicate failure ofbattery 13 if the second data is sent by comparator 27 and if counter 30presents a value higher than a critical value N_(C). Under theseconditions, it has been detected that the voltage V_(bat) at theterminals of battery 13 is within the interval where the test protocolhas to be applied and counter 30 indicates that the test protocol hasalready been applied several times. It therefore seems that the voltagedrop is not linked to a passivation layer or that the flow of a currentat the terminals of battery 13 is not sufficient to break thepassivation layer. Emission of a failure signal makes it possible toanticipate an aggravation of the situation where battery 13 will nolonger be able to supply a sufficient voltage to supply the controlcircuit, the third microcontroller or at least storage circuit 24.

This configuration makes it possible to detect a battery 13 which willnot be functional more rapidly and this enables certain passivatedbatteries 13 to be reactivated without requiring the intervention of auser.

In a particular embodiment, measurement circuit 26 is configured tomeasure the voltage V_(bat) at the terminals of battery 13 as soon as abattery 13 has just been installed.

Under these conditions, a newly fitted battery 13 is automaticallydetected which enables the user to immediately know whether the newbattery 13 intrinsically presents a problem. The situation where a userwho has just fitted a new battery has to come back to change thisbattery which is defective is thus avoided.

Measurement circuit 26, comparator 27 and management circuit 25 can beachieved by distinct electronic circuits or they can be at leastpartially achieved in one and the same electronic circuit for examplethe control circuit and particularly by a microcontroller.

The use of a microcontroller to form at least a part of managementcircuit 25, of measurement circuit 26, of comparator 27 and/or ofcounter 30 is advantageous as this enables a compact device with lowpower consumption to be achieved.

In a particular configuration represented in FIG. 3b , primary electricpower source 2 applies a supply voltage V_(dd) to monitoring device 1via a first diode 31. This configuration is particularly advantageouswhen the primary power supply originates from the power supply line tobe monitored which is an AC or DC power supply.

Voltage V_(dd) is applied to the anode of first diode 31. First diode 31is arranged to supply management circuit 25. The cathode of first diode31 is here connected to the input of third microcontroller 5.

In an advantageous embodiment, first diode 31 is also connected to afirst terminal of a decoupling capacitor 32 configured to smooth thevoltage applied by the power supplies. A second terminal of decouplingcapacitor 32 is connected to the reference potential 23, here theground. Power supply of management circuit 25 by primary power source 2enables the electric battery electric 13 to be economised, the latteronly coming into operation in case of failure of primary source 2.

The same is advantageously the case for the other components involved inmonitoring the state of battery 13, i.e. measurement circuit 26, counter30 and comparator 27.

The anode of battery 13 is connected to the source of transistor 29.Management circuit 25 applies a voltage V_(pol) on the gate of saidtransistor 29, which enables flow of a current from battery 13 (FIG. 3b) to be controlled.

In the illustrated example, the drain of transistor 29 is connected tothe anode of a second diode 31′. The cathode of diode 31′ is connectedto the input of the control circuit and here more precisely to the inputof the third micro-controller. The electric connection between the twodiodes 31 and 31′ with decoupling capacitor 32 defines a second node N₂.Transistor 29 is for example a P-type MOSFET transistor.

In an advantageous embodiment, supply voltage V_(dd), supplied byprimary power supply 2 is about 3.3V with a tolerance of plus or minus5%. The electric voltage V_(bat) of battery 13 is about 3.6V for a fullycharged battery 13.

In one embodiment, decoupling capacitor 32 is a capacitor having acapacitance of about C_(d)=1 μF.

In a particular configuration, first diode 31 and second diode 31′ areSchottky or silicon diodes having a low forward voltage.

In a particular operating mode illustrated in FIG. 3b , the dischargecurrent flows through third microcontroller 5. Electric load 28 isconnected between third microcontroller 5 and reference voltage 23. Anelectric resistance of about 1 kΩ can for example be used to formelectric load 28. In this case, a discharge current I_(d) of about 3 mAis advantageous to ensure degradation of the passivation layer. Thedischarge current is advantageously equal to 3 mA, which correspondswith the embodiment variations to a current comprised between 2.7 and3.3 mA.

In this configuration, a first electric node N₁ is defined by theconnection of the anode of battery 13 with the terminal of the source oftransistor 29 and the power supply input of control circuit 4. Thevoltage V_(bat) of battery 13 can be measured at node N₁ by measuringmeans 26. A second electric node N₂ is defined by the connection of thecathode of first diode 31 with the cathode of second diode 31′ and thesecond input of third microcontroller 5. A terminal of decouplingcapacitor 32 is also connected to node N₂.

In operation, monitoring device 1 can apply the monitoring protocol ofthe state of battery 13 which follows and which is illustrated in FIG.4.

The beginning of the process is represented by step 40, battery 13 ispresent and monitoring device 1 is supplied either by battery 13 or bypower supply source 2. Step 40 can be considered as being a standbystate.

A measurement order is emitted to initiate measurement of the voltageV_(bat) at terminals 13 a of battery 13. A discharge current I_(d) isthen advantageously applied to battery 13 through load 28 in order tobreak the passivation layer and to make on-load voltage measurements.

In a step 41, the voltage V_(bat) at the terminals of battery 13 ismeasured by measuring means 26. Measurement of the voltage V_(bat) canpreferably be made by multiple successive measurements, which enablesfor example a mean of the voltage V_(bat) to be calculated in order toobtain a more reliable value of V_(bat). The discharge current I_(d) isthen interrupted.

In a step 42-43, the measured voltage V_(bat) is compared with the firstand second threshold values V_(min) and V_(OFF).

In step 42, the measured voltage V_(bat) is compared with the firstthreshold value V_(OFF) (V_(bat)<V_(OFF) ?).

If the voltage V_(bat) is lower than the first threshold value V_(OFF)(V_(bat)<V_(OFF)), battery 13 is considered to be defective (step 44)and it is advantageous to replace it.

Advantageously, detection of the defective state is associated withindication of this state to the user (step 45).

Following this indication event, the management method can be terminatedby a waiting phase for replacement of battery 13. Indication can bemade, for example, with an advantageously discrete signal sent by output41 to a light-emitting diode or with a digital or analog signal sent toanother component of the monitoring device. In a particular embodiment,the threshold value V_(OFF) is equal for example to 2.3V.

If the voltage V_(bat), in step 42, is higher than the first thresholdvalue V_(OFF) (V_(bat)>V_(OFF)), the measured voltage V_(bat) iscompared with the second threshold value V_(min). In step 43, themeasured voltage V_(bat) is compared with the second threshold valueV_(min) (V_(bat)>V_(min) ?).

If the voltage V_(bat) is higher than the second threshold value V_(min)(V_(bat)>V_(min)), battery 13 is considered to be functional. This datacan be stored in memory.

The management method then reverts to a waiting state (step 40) or itperforms another measurement step of the voltage V_(bat) (step 41). Inadvantageous manner, the monitoring method reverts to the initial state40 and waits for a new measurement order in order to avoid placing toogreat a load on battery 13.

If the voltage V_(bat) is lower than the second threshold value V_(min)(V_(bat)<V_(min)), this means that the voltage V_(bat) is within thevoltage interval comprised between the first threshold value V_(OFF) andthe second threshold value V_(min). Battery 13 may present a problemthat is able to be corrected.

An additional test protocol of battery 13 is engaged (step 46). Adischarge current I_(d) is again applied on battery 13 through load 28in order to break the passivation layer. In advantageous manner, withthe application of a discharge current I_(d), counter 30 is incrementedin order to know the number of occurrences of this type of problem (step47).

The counter is configured to record the number of iterations ofactivation of the discharge current I_(d). As indicated in the above,the counter records data representative of the number of iterations (n).It is therefore possible to record a time, an electric load, the numberof iterations made or another quantity.

Incrementation of counter (step 47) can be performed before step 46,during step 46 or after step 46.

After a certain application period of discharge current I_(d), thevoltage V_(bat) at the terminals of battery 13 is measured again (step41) in order to measure the evolution of the voltage V_(bat).

As previously, the measured voltage V_(bat) is compared with the firstand second voltage values (steps 42 and 43).

If the voltage V_(bat) is higher than the second threshold value V_(mm)(V_(bat)>V_(min)), battery 13 is considered to be functional. This datacan be stored in memory and it is advantageous to reinitialise counter30.

If the voltage V_(bat) is lower than the first threshold value(V_(bat)<V_(OFF)), battery 13 is considered to be defective and it isadvantageous to replace it. The protocol described above can be applied.

If the voltage V_(bat) is within the voltage interval comprised betweenthe first threshold value V_(OFF) and the second threshold valueV_(min), it is possible to generate a discharge current I_(d) again.

In order to avoid repetition of the discharge current I_(d) at theterminals of battery 13 until the voltage V_(bat) is lower than thefirst threshold value V_(OFF), it is advantageous to introduce acomparison step 48 of the value recorded in counter 30 with a criticalvalue N_(C) (n<N_(C)?). Here again the position of step 48 with respectto steps 46 and 47 is of little importance.

Once the limit value N_(C) has been reached, it is considered thatbattery 13 can no longer be repaired and the battery is considered to bedefective (step 44). The failure protocol is advantageously applied inorder to inform the user.

Thus, if the measured voltage V_(bat) is comprised between the first andsecond threshold values, it is advantageous to make a comparison of thevalue of the counter with a critical value (step 48) in order todetermine whether battery 13 is defective or if a discharge current canimprove the situation. This constitutes an additional criterion enablinga defective battery to be detected.

Steps 42 and 43 can be inverted in so far as it is possible to determinewhether the voltage V_(bat) is lower than the first threshold valueV_(OFF), higher than the second threshold value V_(min) or in theinterval indicated in the foregoing.

In an advantageous embodiment, the management protocol comprises arepetition of certain steps in periodic manner in order to monitor theevolution of the state of battery 13 with time. Advantageously,measurement of the voltage V_(bat) at terminals 13 a of battery 13 isperformed in periodic manner.

In an advantageous embodiment, the management protocol is triggered whena new battery 13 is connected to monitoring device 1. In this way, theuser knows quickly whether the battery 13 is functional or defective.

It is also possible to force the measurement protocol, for example bymeans of a user action either by pressing a push-button 33 or by makinguse of a communication interface.

In a particular operating mode, measurement of the voltage V_(bat), madeduring step 41, can be described schematically in the manner representedin FIG. 5. In the embodiment illustrated in FIG. 5, measurement of thevoltage is performed in cyclic manner. The period is equal to the timeΔt_(m).

If battery 13 is considered to be functional, i.e. if the measuredvoltage is higher than the threshold V_(min), it is advantageous toperform voltage measurement with a first period Δt_(min), for exampleequal to 24 h. If on the other hand battery 13 is considered as beingpotentially defective, i.e. if the measured voltage is lower than thethreshold V_(min) but higher than the threshold V_(OFF), it isadvantageous to perform voltage measurement with a second periodΔt_(m2), for example equal to 19 minutes.

In advantageous manner, when the voltage at the terminals of battery 13is measured within the interval defined by the voltages V_(min) andV_(OFF), a discharge current I_(d) is applied and the voltage V_(bat) ismeasured after a predefined waiting period which follows on fromstopping of the discharge current I_(d).

During the period Δt_(m2), a discharge phase with a current equal toI_(d) is applied. This periodic discharge phase enables the terminals ofthe battery to be made to work to reduce formation of a passivationlayer.

In preferential manner, the voltage measurements are performed after afirst waiting time Δt₁, for example at least equal to 48 ms. This firstwaiting time corresponds to the time separating the end of applicationof the current I_(d) and the first measurement of the voltage V_(bat).The first waiting time enables the voltage measurement to bereliabilized. It is also possible to measure the voltage V_(bat) whenthe current I_(d) is flowing. Here again, it is advantageous to performvoltage measurement in stationary operating conditions, for exampleafter the first waiting time Δt_(t).

As indicated in the foregoing, to obtain a more accurate measurement ofthe voltage V_(bat) at the terminals of the battery, several voltagemeasurements are preferably made. For example, three voltagemeasurements are made.

These measurements are made at times t₁, t₂ and t₃ in FIG. 5. The threemeasurements can be separated by the same rest period or it is possibleto apply a different rest period between the first and secondmeasurements and between the second and the third measurements.

In an operating mode giving good results, a waiting time at least equalto 2 ms is present between two successive voltage measurements.

During the period Δt_(m), there is a discharge phase where the currentI_(d) is applied and a rest phase. During the rest phase, a secondcurrent can be applied. The second current is lower than the firstcurrent I_(d). The second current is advantageously less than half thefirst current I_(d) (in absolute value). It is also possible to have azero second current during the rest phase.

As a variant, during the discharge phase, the discharge current I_(d) isa periodic current with an alternation of discharge periods at a firstcurrent and of rest periods at a second current lower than the firstcurrent (in absolute value) or at zero current.

For example, in FIG. 5, during the period Δt_(m), there is a dischargephase with a current equal to I_(d) from t₀ to t₃ and a rest phase at amuch lower current of I_(d) from t₃ to the end of the period Δt_(m).

For example purposes, good experimental results have been obtained witha period Δt_(m) equal to 19 seconds and a phase t₀ to t₃, where thecurrent is equal to Id, equal to 50 milliseconds for monitoring of thevoltage V_(bat) and depassivation of the battery.

For example purposes, the evolution of the voltage at the terminals ofthe battery is represented in FIG. 6. Until the time A, the measuredvoltage V_(bat) is comprised between the voltages V_(OFF) and V_(min).There is a doubt on the state of the battery which may be functional butpassivated. Until the time A, a discharge current is applied frombattery 13.

From time A up to time B, the voltage V_(bat) is higher than the voltageV_(min) and battery 13 is considered to be functional. Measurement ofthe voltage V_(bat) is performed periodically.

From time B up to time C, the voltage V_(bat) is comprised between thevoltage V_(min) and the voltage V_(OFF). A discharge current is againapplied.

From time C on, the voltage V_(bat) is lower than the voltage V_(OFF)and the battery 13 is considered to be defective.

A device is thus provided which is efficient, simple to produce, andparticularly suitable for the state of a power supply battery 13 of astorage circuit 24.

The invention claimed is:
 1. A circuit breaker comprising a series ofinputs designed to be connected to a first microcontroller configured tomeasure characteristics of an electric current of a power supply line todetect an electric fault of the power supply line, a secondmicrocontroller supplied by said power supply line and presenting afirst electricity consumption value, the second micro-controller beingconfigured to analyse data coming from the first microcontroller inorder to detect an electric fault of the power supply line, a thirdmicrocontroller supplied by said power supply line and connected so asto receive data from the first and second micro-controllers, the thirdmicrocontroller being configured to indicate a cause of tripping of thecircuit breaker, the third microcontroller presenting a secondelectricity consumption lower than the first electricity consumptionvalue, a back-up power supply source configured to supply the thirdmicrocontroller in case of unavailability of the power supply line. 2.The circuit breaker according to claim 1, wherein the thirdmicrocontroller is configured so as to leave a standby state on receiptof a signal from the first and/or second microcontrollers indicatingdetection of the electric fault of the power supply line.
 3. The circuitbreaker according to claim 1, wherein: the first microcontroller isconnected to the second microcontroller by means of a firstcommunication line comprising a first buffer memory separating the firstand second microcontrollers, the second microcontroller is connected tothe third microcontroller by means of a second communication linecomprising a second buffer memory separating the second and thirdmicrocontrollers, the second microcontroller emits a synchronizationsignal to the third microcontroller to define a read priority on saidfirst and second buffer memories.
 4. The circuit breaker according toclaim 1, wherein the first microcontroller is connected to the secondmicrocontroller by means of a first communication line comprising afirst buffer memory, the first microcontroller is connected to the thirdmicrocontroller by means of a second connection line branch-connected onthe first communication line, the second connection line comprising asecond buffer memory, a synchronization signal is emitted by the secondmicrocontroller to the third microcontroller to define a read priorityon the first and second buffer memories.
 5. The circuit breakeraccording to claim 1, wherein the second and third microcontrollers areconnected to a first memory and wherein a synchronization signal isemitted by the second microcontroller to the third microcontroller todefine a read priority on said first memory.
 6. The circuit breakeraccording to claim 5, wherein the first memory is of electricallyerasable and programmable non-volatile memory type or of random accessmemory with permanent magnetic recording type and has a back-up powersupply formed by a capacitor.
 7. The circuit breaker according to claim2, wherein the third microcontroller is configured to leave a standbystate when failing receipt a synchronization signal.
 8. The circuitbreaker according to claim 1, wherein the second and/or thirdmicrocontrollers are connected to a second memory, the second memorybeing connected to near field communicator.
 9. The circuit breakeraccording to claim 1, wherein the second microcontroller and the firstmicrocontroller each have a back-up power supply formed by a capacitor.10. The circuit breaker according to claim 1, wherein the firstmicrocontroller is supplied by means of said power supply line.